Fluid pump or motor

ABSTRACT

TWO RELATIVELY DISPLACEABLE MEMBERS ARE FORMED WITH AT LEAST TWO INTERFITTING SPIROIDAL PERIPHERAL WALL ELEMENTS OR LIKE PITCH, ANGULARLY AND RADIALLY OFFSET TO CONTACT ONE ANOTHER ALONG AT LEAST ONE PAIR OF DIAMETRICALLY OPPOSITE LOCATING SIMULTANEOUSLY, DEFINING TOGETHER WITH ADJOINING SIDEWALLS ONE OR MORE PAIRS OF CHAMBERS OF PROGRESSIVELY VARYING VOLUME UPON A RELATIVE ORBITING OF THEIR CENTERS   WITH SUBSTANTIALLY MAINTENANCE OF THEIR RELATIVE ANGULAR ORIENTATION WHEREBY THE POINTS OF CONTACT SHIFT ALONG THEIR PERIPHERIES, ALTERNATELY OPENING EACH CHAMBER TOWARD AN OUTER AND AN INNER PORT.

a g .I A. .TW'BUSCH .ETAL v --3,56

mm: PUMP on moron 5f Filed D06. 18, 1968 Y 4 Shets-Sheet 1 v Werner Busch Paul Hufnagel V INVENIURS.

Attorney FB.2, 1911 W mi. "3,560,110

I mum rum on uo'ron I Filed D00. 18'. 1968 4 Sheets-Sheet 2 Paul Hufna el.

INVEN'IOR Attorney Werner Bush Feb. 2, 1911 Filed Dec. 18, 1962-:

w. BUSCH ET AL 3,560,119

FLUID PUMP 0R MOTOR I I 4 Sheets-Sheet 3 Werner Busch Paul Hufnagel lNVliN'lORS.

Attorney Feb. 2, 1971 l I w, BUSCH ET AL 3,560,119

I FLUID PUMP OR MOTOR Filed D90. 18. 1968 4 Sheets-Sheet 4.

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Wrnqr Busch Paul Hufnagel INVENTORS'.

Attorney United States Patent 3,560,119 FLUID PUMP OR MOTOR Werner Busch, Munich, Allach, and Paul Hufnagel,

Munich, Germany, assignors to Krauss-Malfei Aktiengesellschaft, Munich, Germany, a corporation of Germany Filed Dec. 18, 1968, Ser. No. 784,841 Claims priority, application Germany, Dec. 18, 1967, P 16 53 815.1 Int. Cl. F02b 53/00; F04c 17/02; B23f 23/08 U.S. Cl. 418-55 18 Claims ABSTRACT OF THE DISCLOSURE Two relatively displaceable members are formed with at least two interfitting spiroidal peripheral wall elements of like pitch, angularly and radially offset to contact one another along at least one pair of diametrically opposite locations simultaneously, defining together with adjoining sidewalls one or more pairs of chambers of progressively varying volume upon a relative orbiting of their centers with substantial maintenance of their relative angular orientation whereby the points of contact shift along their peripheries, alternately opening each chamber toward an outer and an inner port.

Our present invention relates to a fluid-displacement unit, i.e. a pump or a motor, wherein a working fluid is drawn through an inlet port and expelled through an outlet port or, on entering the inlet port under pressure, gives up useful energy to a mechanical load before escaping at the outlet port. It more specifically concerns a unit of the type in which the two ports are sealed off from each other through movable piston means forming fluid chambers that communicate alternately with the inlet and the oulet so that, on standstill, the flow is positively interrupted.

The general object of our invention is to provide a machine of this type that has fewer movable and therefore wear-prone parts than conventional equipment, is considerably more compact for a given rate of displacement, and can be conveniently assembled and disassembled.

A more particular object is to provide a machine of the character set forth which, owing to its robust construction and a continuity of its inner fluid-guiding surfaces, is highly useful as a displacement pump for the delivery of high-viscosity liquids or bulk material.

These objects are realized, pursuant to our present invention, by the provision of two or more mutually interleaved spiroidal Wall elements or webs on two relatively movable members, these elements forming-together with a pair of adjoining sidewalls which may be part of their respective supporting members-several interleaved fluid chambers of generally spiroidal configuration which expand and contract in the course of a cycle in which each chamber communicates first with the outer periphery of the assembly and then with a central port, or vice versa, depending upon the direction of relative motion. The two or more spiroidal wall elements define substantially identical curves which, generally, may be expressed by equations Il =k p for one curve and r'r =k for another curve where k is a constant, r is the length of a reference radius of substantially the same magnitude for both curves as measured from respective axes, r and r are the radial distance of any point of one or the other curve from its respective axis, and o, (p' are the angular distances of these curve points from their respective reference radii. The two axes are mutually parallel and separated by a distance e, referred to hereinafter as eccentricity, which is substantially equal to half the radial distance of successive turns of either the same curve or two curves sharing the same axis. With such an arrangement, as will be shown in greater detail hereinafter, the several wall elements engage one another at two or more points or, more precisely, lines of contact in the plane of the two axes. If, now, the two members carrying the respective wall elements or sets of such elements are relatively displaced to impart to their axes a relative orbital movement with maintenance of the eccentricity e and at least approximate maintenance of the angular orientation of the curves relative to one another, the ensuing rotation of the common axial plane causes a progressive shifting of the lines of contact along the several wall elements. With each wall element extending over approximately 31r radians, a new line of contact is formed between any two adjoining turns of relatively movable elements before the old contact is broken whereby the establishment of a direct flow path from the inlet side to the outlet side is positively prevented at all times.

The curves described above, referred to hereinafter as Archimedean spirals, can also be replaced by related curves, such as involutes of circles of radius r For geometrical reasons it is necessary to terminate at least one spiroidal web short of its axis since otherwise their relative orbital motion could not be performed; this foreshortening of the inner end of one or more webs defines a central port for the admission or discharge of the working fluid. As a limiting case, one web (if shaped as an Archimedean spiral) may be extended to its axis if a co-operating web ends at a minimum radius l' =21rk; in practice, having regard to wall thicknesses and to the esirability of making the two or more webs identical for standardized manufacture, it will generally be advantageous to end each curve at that minimum radius.

Except in cases Where the working fluid is aspirated air or is to be exhausted into the atmosphere,, it will generally be desirable to enclose the assembly within a housing which may form one of the sidewalls of the fluid chambers and may directly support one or more of the interleaved spiroidal wall elements centered on one of the two axes, this housing forming a peripherally disposed outer port for the working fluid. In an advantageous embodiment, the other (mobile) supporting member is then a disk spaced on both sides from confronting housing walls to form a pair of separate compartments therewith, each compartment containing a motor or pump as sembly including a first spiroidal web (or group of such webs) on the respective housing wall and a second such web (or group) on the corresponding disk surface. The two units so formed may operate in parallel or in series on the same working fluid, with their inlet and/or outlet ports interconnected (e.g. through one or more apertures in the disk close to its axis; in a series arrangement, the two sets of spiroids are oppositely oriented with reference to the direction of displacement of the disk so as to establish two generally radial fluid paths, the working fluid moving inwardly on one and outwardly on the other of these paths.

Because of their geometry, the interleaved webs have only limited freedom of relative rotation even if no special detents to inhibit such rotation are provided. If the pressure differential is positive in a radially outward direction, i.e. if pressure at the central port is higher than at the outer port or the atmosphere (as where fluid is peripherally aspirated or force-fed to the central port), the fluid pressure will tend to drive the wall elements apart so that the system will be more or less self-centering; in the reverse case, however, the fluid may in certain positions tend to force the inner edge of one element into wedging engagement with a co-operating element so that jamming could result. Especially in the latter situation, therefore, we prefer to provide means for positively preventing relative rotation of the two supporting members, e.g. a universally jointed rod similar to a Cardan shaft linking the aforementioned disk with its housing or with an eccentric forming part of the disk drive; in the last-mentioned case the rod may be supported on the housing through a nonrotatable swivel head to keep it from turning.

A machine embodying our invention may also be used to extract juices or other filtrates from a relatively viscous mass drawn through the pump chambers as a working fluid; in that case one of the sidewalls, or preferably the edge of a web contacting same, may have passages through which filtrate can escape from the contracting chamber.

The invention will be described in greater detail with reference to the accompanying drawing in which:

FIG. 1 shows a pair of interleaved wall elements according to our invention;

FIGS. 1alk are diagrammatic views of a pair of spiroidal curves drawn to a smaller scale but representative of the coacting wall elements of FIG. 1, in ten different relative positions;

FIG. 2 shows, in axial section, the principal parts of a unit according to the invention;

FIG. 3 is a separate axial section of a disk included in the unit of FIG. 2;

FIG. 4 is a face view of the disk of FIG. 3 in the direction of arrow IV thereof;

FIG. 5 is another diagrammatic view of a modified unit with multiple pairs of spiroidal wall elements;

FIGS. 6 and 7 are views generally similar to FIG. 2, showing other embodiments; and

FIG. 8 is a partly diagrammatic view of a modification of the system shown in FIG. 6 or FIG. 7.

In FIG. 1 we have illustrated two interleaved wall elements s and s of spiroidal configuration as defined above, specifically a pair of Archimedean spirals centered on respective axes O, O' which are offset by an eccentricity e=h/2, It being the pitch or radial spacing between adjacent turns of either spiral and equaling also the minimum radius v or v from which angles in and w are measured. With their respective axes as origins, and with r=r the two curves can be defined by the equations previously given, i.e. rr =k in the case of spiral s and rr =k in the case of spiral s'.

In the relative position illustrated, wall element s contacts wall element s from the outside at a first point P and from the inside at a second point P the two points of contact (actually lines parallel to the axes O, O) lying in a common axial plane P and being spaced 1r radians apart. Curve s also has been shown, in dot-dash lines, extending by 211' radians to its origin 0, thereby forming another inner point of contact with curve s. Each of these curves, starting from its radius vector r or r extends over approximately 1 /2 turns or 3.1r/2 radians. Radii r and r point in opposite directions, thus lying L radians apart. The pitch h is given by 21rk and is of course identical for both curves, depending on the value of constant k. The two elements s, s' have respective wall thicknesses t, t, with r+t=R and r+t':=R; R and R are the outer radii thereof.

If, for the moment, we disregard the wall thickness t, t' and consider only the inner radii r and r of the two curves, we may designate their radii v V in point P and r r in point PH. $1, (PI, and (p $0 1 the corresponding angles of the polar co-ordinate systems centered on axes O and O, we can write for point P and for point P This condition is satisfied for +1r and g0 p '1r which corresponds to the illustrated geometrical relationship and bears out the fact that, with the reference radii r and r pointing in opposite directions, the two curves s, s make two-point contact at diametrically opposite locations with any angular orientation of plane P relative to these reference radii. We also find from Equations 1 and 2 that e=k1r, confirming our initial assumption of 11:22.

If we now introduce the wall thicknesses t and t, Equawhich reduces to Equation 3 if t=t; thus, the two-point contact is maintained independently of the value of i but the eccentricity 2 assumes the modified value k1rl. Generally, the thickness r will be a small fraction of the pitch It so that the relationship e=lz/2 remains substantially valid.

In FIGS. 1a1k we have shown the two curves s and s in simple solid and dotted lines, respectively, these views representing ten different positions of the axis O'-spaced 45 apart-along its orbit of radius a about the axis 0 which is assumed to be stationary; naturally, only the relative motion of the two systems is significant. It will be noted that the angular orientation of curves s and s' remains unaltered throughout the cycle represented by a full revolution of axis 0'. Not shown in these views are two sidewalls perpendicular to axes O and O which, as illustrated in subsequent figures, bound the spaces 12, 12a formed between adjacent turns of spirals s and s. In FIG. 1a the two curves have the relative position of FIG. 1, their points of contact P P lying at 10 and 11 on a vertical line perpendicular to the radii r and r In the following views this line (corresponding to plane P of FIG. 1) rotates clockwise about axis 0. As shown in FIG. 1g, contact P is broken at a point 14 but is substan tially simultaneously re-established at a point 13 on the same radius; a similar situation arises with reference to contact P in a position following by 45 the one illustrated in FIG. 1k.

The spaces 12, 12a form a pair of interleaved, generally spiroidal fluid chambers of varying volume, expanding from the position of FIG 1a to that of FIG. 1g (in which the two chambers are temporarily sealed at both ends) and thereafter contracting again. In their expanding phase they are open toward the outer periphery of the array; in their contracting phase they communicate with a central port in the region of axes O, O. A working fluid in these chambers has been indicated by vertical and horizontal shading, respectively; this fluid enters at the periphery and exits at the center. If the sense of rotation of axis 0 were reversed, the fluid would flow in the opposite direction. It will be understood that this fluid may be aspirated and expelled by positively driven member rigid with spiral s or may impart motion to such member on being admitted under pressure.

If the spirals s and s were extended outwardly beyond the 1 /2 turns shown, additional points of contact would come into existence as more fully described hereinafter with reference to FIG. 5, with duplication of inner and/ or outer contact points at locations 211' radians apart as indicated at P P in FIG. 1. This affords added isolation between the inlet and outlet sides but will usually be required only in the case of major pressure differentials.

In FIG. 2 we have illustrated a simplified version of a physical embodiment of our invention wherein fluid chambers 20, 21 are formed between two spiral webs 22 and 23; web 22 is integral with a wall 2 4 of a housing forming a peripheral inlet port 91 and a central outlet port 92. Web 23 is integral with a driven circular disk 25 whose spacing from wall 24 corresponds to the height H of both webs so that the chambers are fluidtight except at ports 91, 92. The position illustrated for the webs 22, 23 corresponds substantially to that shown in FIGS. 1 and 1a.

FIGS. 3 and 4 show the disk 25 removed from the housing. Axial bores 93 in web 23 may be used to extract a filtrate from a pulpy working fluid as described above, with the web remaining slightly spaced from the confronting wall 24 to let the liquid pass.

A central stem 26 of disk 25 is eccentrically journaled in a bore 27 of a cylindrical bearing member or supporting sleeve 28 rotatably disposed in fixed housing portions 29 and 30 between which a driving gear 31 is secured to the sleeve to apply to it the torque of an external power source not further illustrated. Sleeve 28 and stem 26 are centered on the axes O and respectively, with the aforementioned eccentricity e. In order to hold the disk 25 against rotation, a rod 32 links its stem 26 with a central boss 29a of housing portion 29 via a pair of universal joints 32', 32".

FIG. illustrates, diagrammatically in the manner of FIGS. la-lk, a possible modification of the webs 22, 23 of FIGS. 24 to form multiple spirals s s on wall 24 and s s on disk 25, the fixed spirals s s contacting the mobile spirals s s (dotted) from within at points P P P and from without at points P 1, P in the position shown. Thus there are formed a multiplicity of fluid chambers, such as the one designated 33, functioning in essentially the same manner as in the twospiral arrangement described above. Calculations similar to those made in conjunction with FIG. 1 show that the spirals of each group (fixed group s s and mobile group s s are to be angularly offset by 1r radians from each other and by iir/Z radians from an interleaved spiral of the opposite group, the eccentricity e (neglecting wall thickness) being equal to k1r/2 which is half the radial spacing of adjoining turns of the same group. All the spirally curved webs are again of the same shape, wall thickness and angular extent (approximately 31r/2 radians).

In the system of FIG. 6 we have shown a disk 39 whose surfaces 38a, 38b define two axially spaced compartments A, B with confronting wall surfaces 36, 37 of a housing 38. Spiral webs 43, 44 on disk surfaces 39a, 39b define coacting webs 45, 46 on housing walls 36, 37 two sets of fluid chambers 34, 35 as previously described. These chambers communicate, at different periods, with an inlet 48 open toward the periphery of compartments A, B and an outlet 49 connected with the central ports thereof the disk 39 being apertured at 390 to merge the two central ports into one. A drive shaft 42 centered on axis 0 is rotatably journaled in a housing extension 38a and carries an eccentric 42a coupled through a ball bearing 42b with the hub 40 of the disk centered on axis 0'; a flexible sleeve 50 of rubber or other resilient material surrounds the eccentric 42a and helps retain the disk 39 in its angular position although as noted above, such detent means may be omitted if the pressure in port 49 exceeds that in port 48, as will be the case when fluid is pumped from port 48 to port 49 as indicated by the arrows.

With the arrangement shown in FIG. 6 the two sets of chambers in compartments A and B may be angularly staggered, e.g. by 9'0 in the case of a two-curve system as shown in FIG. 1, to smooth the operation of the unit.

FIG. 7 shows a machine which differs from that of FIG. 6 only in the use of a modified type of detent to prevent rotation of disk 39. A disk 139, otherwise similar to the disk 39 of the preceding embodiment and analogously provided with paraxial apertures 139c, has a center bore formed with flutes 50 to receive teeth 51 on an extremity of a rod 52 which is similarly journaled, via teeth 53 enaging in peripheral grooves 54, in a swivel head 61 rigid with housing 138. The opposite end 52a of rod 52 is coupled via wobbling ball bearings 56 with the head 58 of a drive shaft 59 centered on axis 0, the bearing axis 0 being offset from axis 0 by an eccentricity e the axis of disk 139 is shown at 0 Swivel joints 50, 51 and 53, 54 afford enough peripheral play to let the rod 52 translate the rotation of eccentric 58 into a revolution of axes O 0 about axis 0, the eccentricity 2 of axis 0 being not necessarily equal to eccentricity c and being determined by the location of swivel head 61.

In FIG. 8 we have indicated schematically the possibility of connecting two compartments A, B in series, rather than in parallel as in FIGS. 6 and 7, by using a solid disk 239 in a housing 83 having an inlet at one side and an outlet 81 at the other side of that disk. With the spirals in the two compartments relatively inverted, with reference to the sense of rotation of disk 239, fluid will flow radially outwardly in compartment B and radially inwardly in compartment A after passing around the periphery of the disk which is here completely closed to form a common outer port for the two pump (or motor) assemblies. It will be apparent that a similar effect may be obtained by radially partitioning the peripheral channel 84 and providing its two halves with an inlet port and an outlet port, respectively, to feed fluid into compartment B and removing it from compartment A, or vice versa, with closure of ports 80, 81 toward the outside and interconnection of the central regions of the two compartments via one or more paraxial apertures as shown at 39c, 139c in the preceding two figures.

The word spiroidal as broadly used in the present specification and in the appended claims refers to any curve, such as an Archimedean spiral or an involute (eg of a circle), traced by a point moving around an axis and simultaneously moving away from the axis, e.g. any spiroidal curve.

Advantages afforded by the system in accordance with the invention include the fact that there is relative movement between only two parts and one of these parts can be stationary. There is no requirement for slide or other valves. A simple and robust form of drive means for producing a circular, nonrotary movement can be used.

We claim:

1. A fluid-displacement unit comprising a stationary member and a movable member forming confronting first and second sidewalls, respectively; first and second spiroidal web means respectively mounted on said first and second sidewalls in mutually interleaved relationship, said web means defining at least two substantially identical curves centered on a pair of parallel axes; a housing rigid with said stationary member; sleeve means mounted in said housing for rotation about the axis of said first web means and forming a bearing for said movable member centered on the axis of said second web means, said first and second web means engaging one another along at least two lines of contact in a plane defined by said axes, said sidewalls and said web means together defining a plurality of interleaved fluid chambers of generally spiroidal configuration, said web means having inner ends defining a central port for a working fluid and terminating sufficiently short of said axes to permit a relative orbital movement of said axes with maintenance of constant axial spacing and substantial maintenance of the angular orientation of said curves relative to one another; and drive means for rotating said sleeve means in said housing to effect such orbital movement, thereby progressively shifting said lines of contact along said web means to vary the volume of said chambers and to open each of them alternately toward said central port and toward the outer peripheries of said web means.

2. A unit as defined in claim 1, further comprising detent means holding said movable member against rotation.

3. A unit as defined in claim 2 wherein said housing forms two opposite wall surfaces perpendicular to said axes, said movable member being a disk slidably resting against one of said wall surfaces.

'4. A unit as defined in claim 3 wherein said one of said wall surfaces has a bore centered on the axis of said first web means, said sleeve means being journaled in said bore, said disk having a stem traversing said sleeve.

5. A unit as defined in claim 4 wherein said detent means comprises an elongated link extending generally axially of said sleeve within said housing and a pair of universal joints connecting said link with said stem and with said housing.

6. A unit as defined in claim 1 wherein said housing forms an outer port for said fluid around said outer peripheries.

7. A unit as defined in claim 1 wherein said movable member is a disk further including detent means holding said disk against rotation.

8. A unit as defined in claim 7 wherein said detent means comprises a rod and a pair of universal joints connecting said rod with said disk and with said housing.

9. A unit as defined in claim 1 wherein each of said chambers has at least one apertured wall surface for extracting a filtrate from said working fluid.

10. A unit as defined in claim 9 wherein said apertured wall surface is formed by slots in at least one of said web means.

11. A fluid-displacement unit comprising two relatively displaceable members forming a pair of confronting sidewalls; a first spiroidal web carried by one of said sidewalls and a second spiroidal web carried by the other of said sidewalls in interleaved relationship with said first web, said webs defining two substantially identical curves centered on a pair of parallel axes, said webs engaging one another along at least two lines of contact in a plane defined by said axes; a further web on said one of said sidewalls duplicating said first web in angularly offset coaxial relationship therewith, the starting and termination points of said first and further webs being angularly offset by substantially i1r/2 radians from those of said second web interleaved therewith, said sidewalls and said webs together defining a plurality of interleaved fluid chambers of generally spiroidal configuration, said webs having inner ends defining a central port for a working fluid and terminating sufficiently short of said axes to permit a relative orbital movement of said axes with maintenance of constant axial spacing and substantial maintenance of the angular orientation of said curves relative to one another; and drive means for relatively displacing said members in such orbital movement, thereby progressively shifting said lines of contact along said webs to vary the volume of said chambers and to open each of them alternately toward said central port and toward the outer peripheries of said webs.

12. A unit as defined in claim 11, comprising an additional web on said other of said sidewalls duplicating said second web in coaxial relationship therewith but with an angular offset of 11' radians.

13. A fluid-displacement unit comprising two relatively displaceable members forming a pair of confronting sidewalls; a first spiroidal Web carried by one of said sidewalls and a second spiroidal web carried by the other of said sidewalls in interleaved relationship with said first web, said Webs defining two substantially identical curves generally given by equations rr =k and rr r:k where k is a constant, r is the length of a reference radius of'substantially identical magnitude for both curves measured from respective axes which are parallel to each other and separated by a distance a, r and r are the radial distances of any point of the respective curve from the axis thereof, and (p and are the angular distances of such points from the respective reference radius, 2 being substantially equal to half the radial distance of successive turns about the same axis whereby said webs engage one another along at least two lines of contact in a plane defined by said axes; a further web on said one of said sidewalls duplicating said first web in angularly offset coaxial relationship therewith, the starting and termination points of said first and further webs being angularly offset by substantially itr/Z radians from those of said second web interleaved therewith, said sidewalls and said webs together defining a plurality of interleaved fluid chambers of generally spiroidal configuration, said webs having inner ends defining a central port for a working fluid and terminating sufficiently short of said axes to permit a relative orbital movement of said axes with maintenance of said distance e and substantial maintenance of the angular orientation of said curves relative to one another; and drive means for relatively displacing said members in such oribtal movement, thereby progressively shifting said lines of contact along said webs to vary the volume of said chambers and to open each of them alternately toward said central port and toward the outer peripheries of said webs.

14. A unit as defined in claim 13 wherein said curves are involutes of circles.

15. A unit as defined in claim 13 wherein said reference radii include with each other an angle of substantially 1r radians, the magnitude of r being substantially equal to 21rk-2e.

16. A unit as defined in claim 13 wherein each of said curves extends over substantially 37r radians.

17. A unit as defined in claim 13 wherein said curves are Archimedean spirals.

18. A unit as defined in claim 13 wherein each of said curves starts at substantially 211- radians from its axis.

References Cited UNITED STATES PATENTS 801,182 10/1905 Creux 9156 2,107,090 2/1938 Swennes 103213 2,324,168 7/1943 Montelius 103-137 2,353,373 7/1944 Thompson 103-130 2,475,247 7/1949 Mikulasek 103-130 3,463,091 8/1969 Delsuc 103-131 FOREIGN PATENTS 553,253 2/1956 Canada 230- 367,086 2/1932 Great Britain 103-130 840,970 7/1960 Great Britain 9156 HENRY F. RADUAZO, Primary Examiner US. Cl. X.R. 

